In general, a washing machine may be an upright type or pulsator type washing machine in which a drum that holds the laundry and rotates around a vertical axis, or a drum type washing machine, in which the drum rotates around a horizontal axis.
Since laundry in an upright type washing machine is generally inserted from the top, the upright type washing machine may be referred to as a top loading washing machine, and since laundry in a drum type washing machine is generally inserted from the front, the drum type washing machine may be referred to as a front loading washing machine.
The washing machine generally includes a tub for holding or accommodating water (e.g., washing water) and a drum for accommodating laundry and that rotates inside the tub.
In general, the tub is in a fixed position inside the washing machine, and the drum is mounted or installed inside the tub and configured to rotate inside the tub. The drum may have a plurality of through-holes through which water in the tub may flow in and out.
In a related art drum type washing machine, a motor may be mounted or installed below and/or behind the tub, and the drum mounted or installed inside the tub may be connected with the motor through a rotatable shaft supported by a bearing mounted or installed in the tub wall. A recent drum type washing machine can be mounted or installed on a wall (a so-called “wall mounted” washing machine), enabling installation and use of the washing machine is small or narrow spaces.
The drum type washing machine generally uses less water compared to the upright or pulsator type washing machine. However, a large amount of bubbles, suds or foam may be generated during a washing process.
The bubbles may permeate or accumulate between an external wall of the drum and an inner wall of the tub, which may cause a decrease in the rotation rate or a loss of rotation or rotational force of the drum, thereby causing a waste of energy.